The present disclosure relates generally to the field of drilling wells and more particularly to downhole drilling motors.
In progressive cavity drilling motors, the motor rpm is directly related to the fluid flow rate through the motor. Each motor size is designed to accommodate a range of fluid flow rates. In some downhole drilling scenarios, there is a need for changing the fluid flow rate and/or the rotational speed of bit 150, outside of the design range for the drilling motor in the drill string. A change out of the motor may be required with the attendant removal of the drill string from the wellbore. Such changes are costly in terms of rig time.